A group of law firm workers are discovering the power of the internet as a casually distributed obscene e-mail threatens to cost them their jobs.

The five employees of top law firm Norton Rose will find out their fate on Monday, after facing disciplinary action for their part in a controversial e-mail that eventually mushroomed around the globe.

The e-mail contained a couple of smutty jokes and an exchange which included a female employee giving explicit details of a sexual act.

As soon as we became aware that these rules had been breached we then invoked our internal disciplinary procedures

Bob McAfee of Norton Rose

The e-mail, initially sent on 7 December, quickly passed outside the company to other prestigious law firms in London before making its way across the world.

Up to a million people are now thought to have read what was meant for private consumption amongst friends.

Company spokesman Bob McAfee told the BBC: "These rules are laid down in our terms and conditions of service handbook which is given to all of our employees.

"As soon as we became aware that these rules had been breached we then invoked our internal disciplinary procedures and these are now under way."

After a two-hour hearing, the five law workers were told they would have to wait until Monday to find out whether they still had jobs.

The chain began when the female employee at the centre of the saga sent the two jokes without comment to friends, including her apparent boyfriend.

She then followed it up with a message sent solely to her boyfriend containing the explicit comments.

Bob McAfee: 'Disciplinary procedures now underway'

He forwarded the e-mail to six friends with the comment: "Now THAT'S a nice compliment from a lass, isn't it?".

One of the recipients felt "honour bound" to circulate it further and the chain accelerated.

Within hours dozens of people had seen the accumulated emails, expressing either amusement, sympathy for the original sender, or a desire to track her down.

Internet lawyer Adam Rose said the incident provided a timely warning to employees about the perils of casual e-mail use.

"If they are writing something down that can be distributed around the world, as we have seen from this case, I think people need to take it seriously, they need to give thought to what they are writing down.

"The bottom line is don't use e-mails for sexist material or racist material.

The I Love You email virus caused havoc

"Be prepared to be disciplined or sacked if you do, and I think that's right and proper in the modern day and age."

The incident comes soon after companies gained powers to monitor private staff emails in the Regulation of Investigatory Powers Bill.

Firms such as mobile phone giant Orange have sacked people for misusing internet access at work.

Earlier this year the world's estimated 400m internet users were threatened by the 'I Love You' e-mail virus, which infected millions of computers in just 48 hours.